Studies will be continued on the biologic effects of chronic renal disease. The studies will include an effort: to complete the isolation and synthesis of natriuretic hormone; to examine the nature and component parts of solute specific biologic control systems involved in the functional adaptations that characterize chronic renal disease; to examine the degree to which "trade-off" abnormalities contribute to the symptoms and sign of uremia; and to continue and expand studies using the isolated perfused tubule preparation in a number of different experiments relevant to the pathophysiology of uremia.